Retrospective analysis of the outcomes of pulpotomies in traumatised permanent anterior teeth

Abstract Background/Aim Complicated crown fractures are frequently encountered in the paediatric population and pulpotomy procedures (either partial or coronal) are recommended to maintain the pulp. The aim of this study was to determine the pulp outcomes of permanent teeth with complicated crown fractures treated with pulpotomy in a hospital‐setting and to identify potential factors which may influence the outcomes. Material and Methods Data for this retrospective study were extracted from dental records of patients with complicated crown fractures and treated with pulpotomies at a single centre between 1 January 2015 and 30 August 2019. Pulp outcomes were determined, and the associations between the outcome and independent variables were assessed using the Chi‐Square test of independence and the Point‐Biserial Correlation Test. Predictors of outcome were identified using the binary logistic regression model. Results The overall success of pulpotomy in managing traumatised permanent teeth was 61%, which was lower than those previously reported. Pulp healing was seen in 54.1% and 73.7% of teeth treated with partial pulpotomies and coronal pulpotomies, respectively. The presence of a radiographically detectable dentine bridge (p < .01) and longer clinical experience of the clinician (p < .04) was significantly associated with successful outcomes. The history of pain and the stage of root development were identified as significant predictors of the outcome. Conclusion Pulpotomy is a viable treatment modality for complicated crown fractures in the paediatric population. However, appropriate case selection and further training may be required to ensure improved pulp healing outcomes. A longer follow‐up period should be considered to identify late‐stage complications.


| INTRODUC TI ON
Traumatic dental injuries (TDIs) are frequently encountered amongst the paediatric population and often have long-term consequences. 1 Injuries that result in pulp exposure to the oral environment are described as complicated and they are classified as (1) complicated crown fractures (CCF) or (2) complicated crown-root fractures (CCRF). Some authors do not consider CCRF as a separate entity and classify them as either crown fractures or root fractures. 2 Irrespective of the type of fracture, the sequelae following traumatic pulp exposures are identical and preservation of the pulp should be considered as a treatment priority.
Conservative pulp therapies aim to maintain the remaining pulp and allow continued root development and apex formation in immature teeth. 1 A pulpotomy is a procedure that involves the removal of the inflamed portion of the pulp, thereby allowing the remaining pulp to survive and maintain normal function. The aim of a partial pulpotomy, (also known as the Cvek pulpotomy), is to preserve the cell-rich coronal pulp tissue which has a higher potential to promote healing compared with the radicular pulp. 3,4 Due to its high reported success rates between 86% and 100%, a partial pulpotomy is considered to be the treatment of choice for traumatic pulp exposures. [5][6][7][8][9][10][11][12][13] When necrotic tissue or tissue with obviously impaired vascularity is present at the exposure site of an immature tooth, the pulpotomy should be performed at a deeper level where healthy fresh bleeding can be achieved. 2 A coronal, or cervical, pulpotomy involves the complete removal of the coronal pulp tissue and the placement of a wound dressing at the root canal orifice. 4 The reported success rates of coronal pulpotomies range between 72% and 90.2%. 9,14 In the recently updated trauma guidelines published by the International Association of Dental Traumatology (IADT), there has been a shift in preference to conservative pulp treatment, and partial pulpotomies are now the recommended treatment for teeth with both incomplete and complete root development. 1 Compliance with the previous IADT guidelines resulted in a 95.7% survival rate for teeth with complicated crown fractures. 15 The management of dental trauma is more time-consuming and costlier than the majority of other outpatient accidental injuries. 16 If the burdens of treatment from patient, time and financial perspectives are taken into consideration, it is essential to review the current understanding of the partial pulpotomy technique and the parameters for its success in order for clinicians to provide the best evidence-based care to their patients.
The aims of this study were to (1) evaluate the outcomes of pulpotomy treatment on traumatised anterior permanent teeth with pulp exposures and (2) identify potential factors which may influence the outcomes after pulpotomy by retrospectively analysing clinical data.

| MATERIAL S AND ME THODS
For this retrospective study, data were extracted from the dental records of patients treated at the Department of Paediatric Dentistry and Orthodontics, Westmead Centre for Oral Health (WCOH), Sydney, Australia, between 1 January, 2015 and 30 August 2019.
These patients presented with one or more traumatised permanent anterior teeth requiring a pulpotomy. To be included in the study, the following criteria had to be fulfilled: (1) the traumatised teeth were diagnosed with a CCF or CCRF according to Andreasen's classification, 2 (2) the traumatised teeth were treated with either partial or coronal pulpotomy and, (3) the follow-up period after treatment was a minimum of 9 months with at least two appointments with accompanying radiographs. Teeth of all stages of root development were included. The data obtained from the records included: patient details, dental history, trauma history, details of the initial examination at WCOH, the treatment provided and follow-up details. Ethics The clinical follow-up intervals were not standardised. At the follow-up appointments, any reported patient symptoms, the response to pulp sensibility testing using cold spray (Roeko Endo-Frost, Coltène), mobility, tenderness to percussion, discolouration and radiographic findings were recorded. Healing was considered to have taken place if the tooth was (i) asymptomatic, (ii) had no radiographically demonstrable intra-radicular or peri-radicular pathological changes and (iii) had continued root development if the tooth was immature.
The diagnosis of pulp necrosis (PN) was made when at least two of the following three criteria were fulfilled (1) pain, (2) tenderness to percussion, and (3) a periapical radiolucency. The stage of root development was categorised based on Cvek's classification. 17 Two researchers independently reviewed the radiographs. Where there was disagreement, the radiographs were reviewed together to reach agreement.
The data collected were entered manually into an MS Excel

| RE SULTS
The study population consisted of 50 patients with a total of 60 traumatised teeth requiring pulpotomy treatment. Thirty-three patients were males (66%) and 17 patients (34%) were females. Their ages ranged between 7 and 15 years with a mean age of 10.1 (±2.1) years. Injury was most frequent in the 8-and 10-years-old age groups (20% each), followed by the 9-years-old group (18%). Home/ indoors (24%) were frequently identified as the location of the injury. Falls (34%) were the most common cause, followed by collisions (22%). Patients predominantly sought primary care at WCOH (64%).
Other primary care centres included were the Children's Hospital Westmead (4%), emergency departments of other hospitals (6%), private dental practices (24%) and unknown (2%). The primary care centre was not recorded for one patient (2%). Forty percent of the patients had accompanying soft tissue injuries. Maxillary central incisors (86.7%) were the most frequently injured teeth. CCF (93.3%) accounted for most injuries requiring treatment. Concomitant injuries were identified in 30% of cases, and these included lateral luxation (n = 2/60), subluxation (n = 9/60), extrusion (n = 1/60), mid-root fracture (n = 1/60) and concussion (n = 4/60). The demographics and details of the injuries according to the pulp status at follow-up are summarised in Table 1. There was no significant association between age and pulp healing. Teeth that had sustained CCF had only a slightly improved healing outcome than those with CCRF (p = .65).
In terms of root development, the highest percentage of pulp healing was observed in teeth with stage 3 root development (71.4%).
The time interval between injury and provision of treatment was not significantly associated with pulp healing (p = .31).
The distribution of treatment variables according to the pulp status at follow-up are summarised in Table 2. The outcome of partial pulpotomy was less favourable than for coronal pulpotomy with an  The distribution of post-operative variables according to pulp status at follow-up are summarised in Table 3. Pain at the follow-up assessments was associated with significantly poorer outcomes (p = .001).
Meanwhile, the presence of a dentine bridge at the site of the pulpotomy was associated with a significantly improved outcomes

| DISCUSS ION
The demographics of the study population resembled those reported in the published literature. The maxillary central incisors were the most frequently injured teeth. The frequency of CCF was almost two times higher for males compared with females. One meta-analysis found that males were more likely to experience TDIs than females. 18 Falls, contact sports, automobile accidents and foreign bodies striking the teeth were commonly reported causes of injury in the literature, with many TDIs occurring at home. 2 These patterns were also reflected in this study.
When patients presented with the fractured tooth fragment, where possible, rebonding of the fragment was preferred. Of the 11 rebonded fragments, five were lost between 2 and 51 months and they were subsequently replaced with full coverage resin composite restorations using strip crowns. Reattachment of tooth fragments provides a conservative, aesthetic and cost-effective restorative option. Furthermore, reattachment of the fragment does not affect pulp outcomes in the management of CCF. 19 Andreasen et al. 20  In this study, the overall success rate of pulpotomy was lower than previous studies. 5,7,23,24 This study used Ca(OH) 2 as the pulp capping agent which was consistent with previous studies. Ca(OH) 2 has traditionally been used as a medicament for pulpotomy treatment of traumatically injured teeth with excellent success rates.
Considering the popularity of calcium-based silicate cements (CBSC), it could be suggested that an improved outcome may have been achieved with an alternate material. However, while recent literature report successful outcomes with CBSC for pulpotomies (particularly in the context of pulp therapy for carious pulp exposures), there is insufficient evidence to suggest that they are superior in the management of traumatically exposed pulps. 25 Specific to traumatic pulp exposures, the success rates of Ca(OH) 2 range between 87.5% and 100%, 5,7,8 while the reported success rates of CBSC range between 80% and 99%. 9,[11][12][13] Pulp necrosis was seen in the first 12 months for 60% of the cases. For most forms of TDIs in children, PN has been reported to occur within 6 months of the injury. 6 Cvek 23 found that all cases of PN after partial pulpotomy could be diagnosed within 26 months following treatment and he proposed the need for a 3-year follow-up period. Similarly, Bissinger et al. 19 reported that the mean time interval for PN was 280.9 days (9.2 months), and most cases of PN occurred within the first 2 years after the injury. The IADT recommends clinical and radiographic evaluations after 6-8 weeks, 3, 6 months and 1 year. 1 However, the results from this study and earlier studies suggest that a longer follow-up period is required.
The duration of clinical experience and the radiographic presence of a dentine bridge were the only two variables significantly associated with pulp healing. Compared with GDPs, treatment provided by post-graduate paediatric registrars and specialists had significantly better outcomes. This may be due to the limited experience of GDPs in managing dental trauma in the paediatric population. 26 Additionally, specialists and registrars are more likely to use dental dam, 27,28 which may have also contributed to a higher success rates. The reason for not using a dental dam was not recorded for all patients in this study. This may have been attributed to poor record keeping. Alternatively, possible reasons for not using dental dams may include poor patient acceptance, time required, equipment and material cost, insufficient training and difficulty in use. 29 Treatment in children is often challenging due to behaviour management problems and can present as a stressful experience for a GDP. 30 Dental traumatology and behavioural management are both core components of speciality training in Paediatric Dentistry. Understandably, registrars and specialists were expected to be more knowledgeable and experienced with managing CCF than GDPs. This may translate to a more accurate assessment of the pulp status and improved execution of the procedure.
The presence of a detectable dentine bridge on radiographs was significantly associated with improved pulp prognosis (p < .02) in this study. Rao et al. 11 also found dentine bridge to be more frequently observed in successful pulpotomy cases with Ca(OH) 2  for teeth with both immature and mature roots, and they concluded that the stage of root development did not affect the treatment outcome. 5,7 In terms of pain history, pulp healing was more likely to occur in teeth where the patient did not report pain at the follow-up appointments. Of the 19 teeth with a history of pain, PN was seen in 13 (68.4%). The pain resolved in the remaining six teeth (31.6%).
Further investigation will be required to identify the cause of the pain and the factors which contributed to its resolution.
One of the major limitations of this study was the lack of standardised clinical records. The missing data meant that the sample size was small and statistical analysis could not be performed for all variables. Another limitation was that many teeth were excluded due to insufficient follow-up. In many instances, the patients were discharged back to their local dentist or to their local oral health clinics. Patients that had subsequent injuries or had reported symptoms were more likely to be followed up at WCOH. This would have likely skewed the study population towards a poorer outcome and may explain the lower success rate of pulpotomy in this study when compared with those reported in the literature. While pulpotomy remains a viable treatment option, appropriate case selection and further training in the use of dental dam in the hospital setting may be required to ensure improved pulp healing outcomes. The development of clinical protocols for trauma scenarios in line with evidence-based procedures would also be advantageous for better outcomes. Furthermore, a longer follow-up period should be considered to monitor for late-stage complications.

AUTH O R CO NTR I B UTI O N S
None.

ACK N OWLED G EM ENT
Open access publishing facilitated by The University of Sydney, as part of the Wiley -The University of Sydney agreement via the Council of Australian University Librarians.

CO N FLI C T O F I NTE R E S T
The authors confirm that they have no conflict of interest.

DATA AVA I L A B I L I T Y S TAT E M E N T
Data sharing is not applicable to this article as no new data were created or analyzed in this study.